


Thermal Equilibrium

by lomku



Category: Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Character Study, Fluff and Angst, Getting Together, Hurt/Comfort, M/M, Mutual Pining, Steve Feels, Tony Feels
Language: English
Status: Completed
Published: 2020-05-05
Updated: 2020-05-05
Packaged: 2021-03-03 00:13:47
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,687
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24025648
Author URL: https://archiveofourown.org/users/lomku/pseuds/lomku
Summary: Steve wakes up and he’s cold. He has felt cold ever since he got out of the ice.Tony wakes up and he’s hot. He’s been too hot ever since Afghanistan.Together, they find a middle ground.
Relationships: Steve Rogers/Tony Stark
Comments: 35
Kudos: 194





	Thermal Equilibrium

**Author's Note:**

> My first stony fic, enjoy!

Steve wakes up and he’s cold.

It doesn’t matter how many blankets he burrows himself in, how thick the fabric of his pyjamas is. It doesn’t matter if he has the temperature in his room set to well over 25 degrees Celsius. It doesn’t matter, it doesn’t matter.

Steve has felt cold ever since he got out of the ice.

It’s a constant in his life, _you’re cold_ , right along _you’re 70 years in the future_ and _everyone you knew and loved is dead_ and _you’re alone_. He asked the SHIELD doctors, once, a few days after waking up, “Why is it so cold in here?” and they looked at him with confused faces and took his temperature. 35,3 degrees, it said. A bit low, but in the range of a normal human’s temperature. It’s to be expected, they said, with a supersoldier body and fast metabolism the energy goes towards other things, and your heart is beating at a slower pace than the norm, so you should be a bit low. But don’t worry! You don’t have fever or anything.

He didn’t tell them that that wasn’t his question.

His body temperature is a bit low, but his extremities are freezing. He takes to wearing thick socks and his suit gloves as often as he can, just to feel a little bit of warmth. The team jokes about it, something about him being always ready for action, and he lets them.

They don’t know about his condition.

He looked it up, one particularly bad night, when his teeth were shattering and his bones rattling inside his body, and JARVIS’ quiet voice had assured him that he was in Avengers Tower, New York, that the year is 2012, he’s safe, he’s awake. He asked then. Why was he always cold? Shouldn’t he be the pinnacle of human perfection? Was there a fault in the serum?

And JARVIS told him about post-traumatic stress disorder, and panic attacks, and flashbacks. Told Steve he could get help if he wanted. Steve smiled at the camera in the ceiling, told him he was fine, thank you, and put the blanket over his head. He didn’t ask JARVIS again and JARVIS didn’t press.

Steve doesn’t like to think about the cold.

But he can’t shake it off. He dreams of it, of falling in the icy water, of the slow rise of the ocean into the Valkyrie’s cockpit, his ragged breathing the only sound apart from the groaning of the aircraft, the endless darkness of the water as he sinks, sinks, sinks, until there’s water everywhere, around him, above him, inside him.

Sometimes he thinks his body never really recovered.

His skin is always cold to the touch, something it wasn’t before the ice. Before, the Howlies would tell him he ran hot like a furnace, tell him jokingly he was the most comfortable radiator they’d ever had. They would touch him, a pat on the back, a hand on the shoulder, a hug after a too dangerous mission. Sometimes, when they were sleeping in the snowy forests of France, they’d huddle together, practically sleeping on top of each other, and Steve would keep them warm.

These days, he can’t even keep _himself_ warm.

His hands are cold, and other people notice. Every time he shakes hands with someone, there is a flicker of surprise, followed by an almost unnoticeable shiver. He makes them cold, he realises. After they’ve shaken his hand, they flex theirs, or rub their hands together to get some heat back.

Steve thinks he leaches the heat out of them, like a vampire takes blood of living creatures to keep existing a little longer, never alive, never dead. Steve wonders if he would die faster than a baseline human if he was left alone somewhere cold, without any heat to suck out of someone.

Would he turn to ice, shatter in the wind? Or would he tremble and shiver and shiver until there was nothing left of him?

His dreams don’t give him any answers.

He avoids touching people, because he can’t stand the look on their faces when he robs them of their heat.

It’s better to avoid touching them. Easier, both for them, and for him. If he touches someone, it’s always with at least one layer of cloth between his hand and the person.

He misses touching people, but it’s just something else he has to deal with.

He can deal with it.

He just needs to think of something else. Just move on, soldier, keep going, and think about the next mission.

It helps, not being in his little apartment in Brooklyn anymore, where the walls are too thin, and the wind is biting. Now, he’s in the Tower, with adjustable room temperature and an endless supply of hot water and heavy blankets. And when he feels too cold, when he wakes up with his throat aching from the screaming but he doesn’t dare drink a glass of water because he’s sure it’ll turn into ice as it slides down his throat, he can take the elevator to the sauna, or the common rooms, hoping that someone else is going to be awake.

It’s always better when he isn’t alone. It takes his mind off everything, allows him to keep himself in the present, to shut out his ghosts.

He likes the team. They’re all very different, each with their own personality and history and demons. They’ve managed to form a close group, and during the good days, he can admit to himself that they are friends.

Five months ago, he’d never have guessed that they would get along, but five months ago he was still in the ice, so.

It still feels like a dream, most days. Some nights, he dreams of waking up in his own time, Peggy looking down at him and smiling, Howard boasting about how they found him in less than a day. He always wakes up crying from this dream, and it’s all he can do to drag himself out of bed and down to the kitchen where he’ll pretend he isn’t falling apart from grief in front of his team-mates.

Thankfully, they don’t mention his shaking hands or bags under his eyes. It’s a small mercy, but he’ll take it. They never mention their nightmares, or when others clearly look like they haven’t slept at all during the night. They all have their trauma, and it reassures Steve, to know he’s not the only one.

He can hear better than most, which is why he hears Tony scream, one night, when he walks past Tony’s door, his own thoughts full of ice and darkness.

He goes down to the kitchen and sets a pot of coffee, and Tony comes down a few minutes later, eyes haunted and shoulders hunched. They don’t talk, but it’s comforting nonetheless. Tony motions to the TV, and they end up watching a movie together. Tony falls asleep in the early hours of the morning, and Steve watches him, his fluttering eyelids, the cool glow of the reactor, his rough hands and the slow rise and fall of his chest.

Tony’s beautiful.

Steve has always known that, but now he can’t help but notice.

Steve firmly shuts down the half-formed thoughts of sketching Tony and closes his eyes.

During the next weeks, he watches Tony, and watches, and watches, and watches.

He starts seeking Tony out, and Tony doesn’t mind, even when he starts sketching in the workshop, trying and failing to draw anything but Tony, Tony’s eyes, Tony’s hands, Tony’s body in a graceful dance of creation.

As they become better friends (and isn’t that wonderful? That they managed to get past the antagonism and hurting remarks of the early days), they spend more time together, and Steve realises he won’t be able to ignore the warmth that spreads in his chest every time he sees Tony.

He can’t get enough of Tony, and he _wants_ , he wants more of Tony, of the laugh-lines on his face, his curly hair, the quiet touches when Steve can’t feel his own skin, his eyelashes, his arms, his laugh, everything.

They start touching each other, little pats on the back or playful taps when they’re mock-arguing over something. At first, Steve is wary, because Tony’ll surely stop when he feels how cold Steve is. But Tony never stops. He doesn’t mind the cold, and just crowds closer, and Steve lets himself touch Tony back.

Tony’s touches are searing hot, and Steve can’t keep away from them. He comes back to Tony, like a moth to a flame, and he relishes the burn.

Steve thinks he might be addicted to Tony and his heat. Every time they touch, the warmth lingers, on his arm, on his shoulder, wherever Tony’s hand has been, and Steve forgets the cold.

* * *

Tony wakes up and he’s hot.

Not in the fun way.

He’s been too hot ever since Afghanistan. It’s almost inconsequential, when you think about it. So much is different since Afghanistan, so this shouldn’t be so important. But it is. It’s always in the back of his mind, _I’m hot_ , right next to _my lungs ache_ and _I need to be better do better fix things atone for everything I’ve ever done._

The thing is, there are many drawbacks to having an arc reactor inside his chest.

The obvious, of course, being that a third of his lungs are gone, irreparably. He can’t take deep breaths, can’t run as fast or as long as before, can’t climb up several flights of stairs without getting out of breath. He’s been training, using techniques that people with asthma use to avoid being short of breath all the time. His breathing is always controlled, always even.

Then there’s the pain. It hurts, to have something alien in your chest, pushing against bone and muscles and tissue, crushing his heart if he lies down the wrong way. He can’t stretch all the way, can’t raise his arms higher than a certain point, can’t lie on his stomach. It’s a constant ache, but it can get worse if he makes a wrong movement, if he takes a hit in the suit, if he has bruises on his chest.

Tony doesn’t know what it’s like to live without pain, not anymore.

There are the infections, too. The casing was never made to be put inside his chest, and it shows. He’s learned to use hand sanitizer more often than not, avoid people when they’re showing the smallest hints of having a cold or the flu. His immune system is shot to hell, and it was even worse when he had the palladium poisoning. He still gets infections around the casing, sometimes.

This is something he hasn’t told anyone: the casing of the arc reactor, the tube that goes down and down and down into his chest, is a cannibalised part of a Stark missile casing. It was the only thing that Yinsen could use. The original arc reactor was also made of missiles, but he changed that as soon as he got out of the caves. He can’t change the casing, and he hates that one of his _weapons_ is keeping him alive. It sits in his body, taunting him, and it will stay there until he dies.

If he could, he would rip it out of himself. He’s dreamt of it.

Which brings him to the last major drawback of his arc reactor: the heat. The reactor works with cold fusion, of course, because otherwise he’d be cooking at millions of degrees. But cold fusion is only relatively cold. Tony has measured temperatures, of course, and what comes out is this: the interior of his arc reactor reaches several hundred degrees, and the casing around it and insulating glass manage to drop the temperature to between 50 and 60 degrees. Which is still very hot, especially since he has that inside his body.

When he put in the first arc reactor in the cave, he panicked, convinced something had caught fire. But then he realised that it was just his chest. The burning sensation stopped after a few hours, or rather it faded into the background. Nowadays, Tony can barely feel it, just an itch in the back of his mind.

It’s after a few days that Tony realised what exactly it meant to have a heat source in his chest. 

He was never cold in the caves, even with the freezing nights and even colder waterboarding. In fact, Tony was always sweating, his skin hot and clammy. It made him drowsy and dizzy, the constant heat, as if he had a fever.

It saved his life when he got out of the caves and collapsed from exhaustion during that first and last night in the desert. He’d have died of hypothermia, if he hadn’t had his own personal heater to keep him warm.

Tony burned himself when he changed arc reactors. He waited as long as he could before calling Pepper, to let the casing cool before her hand got anywhere near it. Avoiding a short-circuit wasn’t the only reason why he told her not to touch the sides.

He has burn scars on his chest, above the ones from the shrapnel and the operation. They surround the casing in a neat white circle.

The new arc reactors all have insulated glass, which means they have three layers of glass separated with vacuum to insulate from the heat generated by the reactor. They’re a bit heavier, but it’s better than burning himself every time he needs to work on them.

His internal body temperature is fine, maybe a little bit higher than before Afghanistan (he can’t avoid the low-grade fevers he gets from the infections), but his surface temperature is off by several degrees. He sweats a lot, has to wear lighter clothing, has to be careful when he goes to a board meeting or when he meets other people. He takes to wearing pants and shirts that don’t let sweat through, because he quickly realised he left sweat stains everywhere he sat. He always has a handkerchief nearby, to dry his hands before he shakes someone’s hand, to dab at his forehead.

He keeps his workshop and living spaces cool.

Pepper and Rhodey mentioned it, when they realised how cold it was in his house, and he deflected, told them the heat reminded him of Afghanistan. They never mentioned it again.

He manages, all in all.

What he misses the most, though, is touching people. He knows his hands are clammy, that people get uncomfortable around him if they sit too close to him. He’s seen how Pepper discreetly fanned herself after their dance at that charity auction, how Rhodey wiped his hands on his pants after helping him out of the car in the middle of the palladium debacle. They don’t say anything, of course, they’re too kind for that. But Tony noticed, so he doesn’t touch them as often, after that. A pat on the shoulder, sure, or a quick squeeze of his hand, but always with clothes between him and their skin.

It still gets lonely.

He wants nothing more than to hug someone, have someone in his arms, maybe even in his bed, but he knows it’ll only ever be a dream.

He manages.

Besides, it could be worse.

He doesn’t live alone anymore, at least. There’s the Avengers, that rag-tag team he somehow managed to become a part of.

He even likes them, incredibly enough. Even Steve. Or maybe he should say _especially_ Steve. After their more than rocky start, they eventually talked it out. And, sure, they argue a lot, but the arguments have lost their heat. In fact, it could almost be called teasing. And Tony likes that, a lot. He likes spending time with Steve, who has proven to be everything but the stuck-up asshole Tony thought he was. He’s very human, Steve. He’s grumpy when he wakes up, always eats the same bowl of cereal with too much sugar in the mornings, has his own little routines. He talks calmly, smiles politely, but sometimes he gets lost in his head, his eyes far away, and goes quiet. Tony always talks to him when that happens, and he pretends nothing was wrong when Steve answers.

They spend a lot of time together, Steve and Tony. Tony likes to work on SI stuff in the common room, and Steve’s almost always there, reading a book or sketching on the couch, when he isn’t in the gym.

Tony realises Steve is touch-starved when he touches him after a particularly bad night. It goes like this: Tony wakes up from a nightmare and decides he’s not going to sleep again. He goes down to the kitchen, planning to brew himself a pot of coffee and disappear down to the workshop for a day, and Steve is sitting on the couch, huddled in a blanket, staring blankly through the windows. He’s shivering, Tony notices. So Tony does the sensible thing and offers to rub Steve’s back, spouting some bullshit about heat and friction and not thinking too much about how this means he’s going to _touch_ Steve, who he may or may not have feelings for. And Steve, in the quiet and self-effacing way he has, tells him it’s _kind, Tony, but I’m fine_.

Steve is definitely _not_ fine, and Tony should know, because he’s an expert in being not-fine.

So Tony insists, and Steve must be very tired, because he relents and lowers the blanket a little bit. He’s wearing a thin shirt, and Tony’s grateful for that, because he doesn’t know what he would have done if Steve had been shirtless.

He rubs Steve’s shoulders and upper back, and Steve shudders violently, then melts into his touch. Tony doesn’t mention it, but he spends longer than necessary with his hands on Steve, even giving him a small massage. The considerable amount of tension in Steve’s back releases after a while.

Tony realises Steve has fallen asleep when he hears a quiet snore.

He puts the blanket back around Steve, lowers him to the couch, and makes a mental note to touch Steve more often.

He does, and it works out wonderfully, because Steve starts touching him more too.

At first, it makes Tony nervous, but he never sees Steve wipe his hands, or fan himself, or grimace after spending a long time in Tony’s close vicinity, and Tony realises with a jolt that Steve doesn’t mind the heat. If anything, Steve seems drawn to it, and Tony is in turn drawn to Steve, who is always pleasantly cool to the touch, just enough to quell the slow fire that burns inside Tony.

They sit closer to each other, and if the rest of the team notices, they don’t mention it. Tony’s pathetically graceful for that, because this thing he has with Steve is still too fragile. He doesn’t know what Steve thinks, but he has the suspicion that Steve would draw back into himself if someone made a joke about them getting touchy-feely with each other.

It’s nice, and it’s good, and Tony silently aches for more.

He _wants_ , he wants Steve’s smiles and the laughs that are still too rare, he wants Steve’s hugs, and the twinkle in his eyes, and his touch, and his hands, and his mouth, and his everything. Tony wants and wants and wants, and spends even more time with Steve.

After a few months, he can’t stop himself: he starts flirting with Steve. Natasha picks up on it after a day, and Bruce asks him about it the next week. Tony can’t explain why, other than he wants.

Steve doesn’t really act differently, so Tony continues with the lingering touches and private smiles. Steve is more settled, he’s less often lost in his own thoughts. He smiles more. He starts…he starts flirting back.

_He starts flirting back._

There is no other explanation to his half-lidded eyes on Tony in the evenings, on his new-found love for ice-cream and syrup on his pancakes, on his hand on Tony’s hip as he walks past.

They dance around each other, and Tony forgets his pain, his regrets, the heat, when he’s with Steve and his cool hands and warm smile.

The tipping point is a quiet autumn night, after a team movie evening. The rest of the team has gone to bed, but Tony and Steve are still in the common room, sitting on the couch and talking about some insignificant detail of the movie. They don’t even realise they’re alone until Steve looks up and goes wide-eyed at the absence of their team-mates. And usually that is where Tony would tell him good night and retreat, but he’s not very tired, and Steve’s eyelashes are distractingly beautiful in the low light.

They’re sitting very close, he realises. He can count the slight freckles on Steve’s cheeks, see the dilating of his pupils, the tongue licking his lips.

Steve takes a deep breath, and takes Tony’s hand. Instantly, a little bit of Tony’s fever abates.

Tony cups Steve’s cheek, silky smooth and cool, and then they’re kissing.

It’s everything Tony has imagined, and more. There is none of the scorching heat, but all of the passion. Tony touches and caresses and gropes and closes his eyes and stutters out a breath when Steve does the same. Steve kisses the feverishness out of Tony, replacing it with a pleasant cold, making him shiver in the dark. Steve pants in his mouth, cheeks redder than Tony has ever seen them, his hands all over Tony, and Tony lets himself get swept away.

* * *

Steve wakes up and he isn’t cold. He isn’t in his own bed either. There’s a pleasant heat on his back, radiating through him, making him feel warm and content, down to his fingers. A whisper of lips on his neck, arms wrapping tight around his chest, legs tangled with his. Steve lets himself feel Tony against him, and smiles.

**Author's Note:**

> Comments make my day, even if it's just a word or an emoji! <3


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